1. Technical Field
The present disclosure relates to a coating forming material, and more particularly, to a coating material for a photoresist pattern and a method of forming a fine pattern using the same.
2. Description of the Related Art
A plurality of patterning processes are employed in manufacturing electronic components such as a semiconductor device and a liquid crystal display (LCD). A technique including forming a photoresist pattern on a substrate, and forming a variety of fine patterns on the substrate using the photoresist pattern as an etch mask is employed in the patterning process. Research aiming at reducing the fine patterns to meet demand for light, thin, short and small electronic parts is underway.
The minimum size of the photoresist pattern may be determined by the resolution limit of an exposure apparatus. A technique for forming fine patterns smaller than the resolution limit of the exposure apparatus includes performing an annealing process to cause the photoresist pattern to flow. The flow depends on the volume of the photoresist pattern. That is, forming a plurality of photoresist patterns having different sizes on a substrate may result in difficulty in uniformly increasing or reducing the shape and size of the fine patterns. For example, the occurrence of overflow may cause a gap region between patterns to be buried.
Another technique for forming fine patterns smaller than the resolution limit of the exposure apparatus includes forming a coating layer on surfaces of photoresist patterns using a coating forming material.
Meanwhile, another method of forming a fine pattern using a coating forming material is described in U.S. Patent Publication No. U.S. 2005/0123851 entitled “Coating Material for Pattern Fineness Enhancement and Method for Forming Fine Pattern with the same” to Shinbori.
According to Shinbori, a coating forming material formed of a water-soluble polymer and a water-soluble cross-linking agent is provided. Also, a method of forming a fine pattern using the coating forming material is provided.
Meanwhile, the coating forming material should not melt the photoresist patterns and should readily remove the slurry left after reaction. The conventional water-soluble polymer has hydroxyl groups (—OH). The hydroxyl groups (—OH) can form intramolecular hydrogen bonding (Hb). The intramolecular hydrogen bonding (Hb) may serve as a crystallization point. In addition, the intramolecular hydrogen bonding (Hb) may inhibit the water-soluble polymer from being dissolved in water. In this case, a gap region between the photoresist patterns may be buried by a polymer slurry. That is, when slurries left after the reaction of the coating forming material remain on the photoresist patterns, defects such as contact hole clogging and micro-bridging between patterns may occur.
Furthermore, the hydroxyl groups (—OH) may cause difficulties with cross linking.